Area Forecast Discussion
Issued by NWS San Joaquin Valley, CA
Issued by NWS San Joaquin Valley, CA
735 FXUS66 KHNX 051102 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 402 AM PDT Fri Jul 5 2024 && .KEY MESSAGES... 1. A dangerous, long-duration heat wave will continue to impact Central California throughout the holiday week, the weekend, and into next week. 2. An Excessive Heat Warning remains in effect through 11 AM Thursday, July 11th. 3. A Red Flag Warning remains in effect until 12 PM Friday, but until 6 AM Saturday for southwestern Kern County. 4. The risk of grass fires will continue to increase with herbaceous fuel loading at or near 120% of normal. A long period of excessive heat, minimum relative humidities near 15% and poor overnight relative humidity recovery continues. && .DISCUSSION... A very strong ridge continues to hold its grip over the southwest, resulting in high temperatures around 15 degrees above normal and very poor overnight recovery. This ridge is currently a more latitudinal orientation, but we move into the weekend, it will turn and become more longitudinal and the axis of the ridge will be directly over Central California. This will lead to a further increase in high temperatures and an overall increase in the total area of Extreme Heat Risk. Using probabilities to illustrate this increase, the chance for a high of 110 degrees or more in the San Joaquin Valley today is 20-45%, whereas the chance for 110 degrees or more for this weekend is 60-80%. After the weekend, the movement of the ridge will be dependent on the movement of Hurricane Beryl. The tropical system is likely to follow the trough currently over the eastern CONUS and get absorbed into the main flow, which would slowly pull the ridge to the east over the next week. This would put the axis over Arizona and would slowly bring down high temperatures in the valley. They would still be above normal, just not above 110 degrees as they are forecast this weekend. The models are also showing a split in the ridge, lasting from Tuesday into next Friday, resulting in a mini trough over the Californian coast. If there is enough moisture with it, there is the possibility for some thunderstorms, though if it continues to be as dry as it is right now, that would cause it to be breezy in our area. Keep in mind that this is in the long term forecast, so confidence is not high and it will more than likely change in the coming days. && .AVIATION... MVFR and local IFR visibility due wildfire smoke will continue. These areas of smoke may increase. Otherwise, VFR conditions will prevail across the central California interior for the next 24 hours. && .FIRE WEATHER... A Red Flag Warning remains in effect for the San Joaquin Valley and the Kern County Mountains until 12 PM today, with a portion of southwestern Kern County until 6 AM Saturday. This is due to very low minimum relative humidities near 15%, breezy winds with gusts up to 20 mph, above normal temperatures, and very dry fuels, increasing the risk for fast-moving grass fires. The risk for fire starts has also increased due to the holiday activities late last night. The Warning may need to be extended into the Mojave Slopes due to increased winds with gusts of 20-30 mph later tonight, paired with minimum relative humidities in the single digits. && .AIR QUALITY ISSUES... ISSUED: 07/04/2024 10:50 EXPIRES: 07/05/2024 23:59 None. && .CERTAINTY... The level of certainty for days 1 and 2 is medium. The level of certainty for days 3 through 7 is medium. Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback. && .HNX WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 11 PM PDT Thursday for CAZ300>322- 324-332-334>339. Red Flag Warning until noon PDT today for CAZ579-580-590-591- 596. Red Flag Warning until 6 AM PDT Saturday for CAZ597. && $$ Public/Aviation..................EW DSS/PIO/Fire Weather.............VJP weather.gov/hanford